United States Office of Water EPA-822-F-02-005

Environmental Protection 4304T June 2002

Agency

Fact Sheet

Notice of Data Availability for Dioxins in Land-Applied Sewage Sludge -

Round 2 Part 503

Summary

This Notice of Data Availability (NODA) summarizes new data and a revised risk assessment

and invites public comments on this information. In December 1999, EPA proposed a numeric

standard for dioxins in sewage sludge which is applied to agricultural land. The Agency based

its proposed limit on the results of a risk assessment for dioxins in land-applied sewage sludge. 

Since the proposal, EPA gathered new data and conducted a new risk assessment. We will

consider comments we receive during the 90-day public comment period in formulating the final

action.

The Round 1 Sewage Sludge Regulation

Part 503 is the comprehensive regulation for land application, surface disposal, and incineration

of sewage sludge under section 405 of the Clean Water Act. Section 405 calls for two “rounds”

of regulation: Round 1 addresses pollutants for which information was available at the time, and

Round 2 addresses additional pollutants. Because EPA did not meet the statutory deadline for

the Round 1 regulations, the Agency was sued and entered into a consent decree establishing a

schedule for both the Round 1 and 2 regulations.

In February 1993, EPA published the Standards for the Use or Disposal of Sewage Sludge. 

Known as the Round 1 sewage sludge regulation, these standards contain the requirements for

sewage sludge that is applied to the land, placed in a surface disposal unit, or fired in a sewage

sludge incinerator. The Round 1 rule has been amended several times since then.

Proposed Round 2 Rule

In December 1999, EPA proposed to amend management standards by adding a numeric

concentration limit for dioxins in land-applied sewage sludge. Based on our initial risk

assessment, the proposed limit would prohibit land application of sewage sludge that contains

more than 300 parts per trillion toxic equivalents of dioxins. EPA proposed this limit to protect

public health and the environment from unreasonable risks of exposure to dioxins. 

EPA also proposed to exclude the following from the numeric limit and monitoring

requirements: treatment works with a flow rate equal to or less than one million gallons per day

and certain sewage sludge-only entities that receive sewage sludge for further processing before

its application to land. We based this exclusion on the small amount of sewage sludge that these

facilities handle. 

In December 1999, EPA also proposed not to regulate dioxins in sewage sludge that is placed in
a surface disposal unit or fired in sewage sludge incinerator on the basis of separate risk

assessments for those management practices. EPA made a final decision to sustain that

determination in December 2001.

Developments Since Proposal

In 2001, EPA conducted a survey to update its information on the concentrations of dioxins in

sewage sludge. The Agency also performed a revised risk assessment for dioxins in land-applied

sewage sludge. We are seeking comments on the updated survey and the findings of the revised

risk assessment, both of which are presented in this NODA. The NODA also summarizes a

survey of dioxins in sewage sludge conducted by the Association of Metropolitan Sewerage

Agencies .

In addition, the NODA discusses the implications of the new data and revised risk assessment on

the proposed limit, monitoring requirements, small entity exclusion and projected cost of the

proposed regulation. Finally, the NODA discusses how our risk estimates for the highly-exposed

population could be affected by the Agency's Draft Dioxin Reassessment if it becomes final

before we complete this rulemaking.

Additional Information

For additional information, contact Alan B. Hais at (202) 566-1106 or Alan B. Rubin at (202)

566-1125.

You can find other sewage sludge information on the Internet at

http://www.epa.gov/waterscience/biosolids/.